We utilize county-level data to explore the roles of different types of human capital accumulation in U.S. growth determination. The data includes over 3,000 cross-sectional observations and 39 demographic control variables. The large number of observations provides enough degrees of freedom to...

In this paper we outline (i) why ó-convergence may not accompany â- convergence, (ii)cite evidence of â-convergence in the U.S., (iii) and use USA county-level data containing over 3,000 cross-sectional observations to demonstrate that ó-convergence does not hold across the U.S., or within...

We use county data with 3,058 observations to study growth and convergence in the US. We assess the effect of 40 conditioning variables on the counties’ balanced growth paths. Using OLS and 3SLS-IV, the later yielding consistent estimates, we report estimates for the full sample and for metro,...

We use U.S. county data (3,058 observations) and 41 conditioning variables to study growth and convergence. Using OLS and 3SLS-IV we report on the full sample and metro, non-metro, and 5 regional samples: (1) OLS yields convergence rates around 2 percent; 3SLS yields 6–8 percent; (2)...

I show that in a conventional Ramsey model, between one-fourth and one- half of income differences across countries can be explained by a single factor: The steady-state effect of large, persistent differences in national average IQ on worker productivity. These differences in cognitive...